This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Recently there has been an increasing amount of research into the field of near-eye displays. Generally these includes some micro display such as a liquid crystal panel onto which data is displayed, and a separate illumination source for adding brightness and preferably color to the information on the micro display. The overall near-eye device then has various arrangements of lenses, mirrors, and the like to optically impose the brightened image from the micro display into a user's optical field of view. Such liquid crystal micro displays can be transmissive or reflective. Being near-eye display devices, weight, power consumption and spatial compactness are some driving design considerations. Of these, spatial compactness has generally been the more difficult engineering obstacle to overcome without adversely impacting quality of the image seen by the user, because it is quite difficult to maintain optical quality through the optical engine which is subject to such severe mechanical/size constraints.
One technical near-eye display solution is detailed at U.S. Pat. No. 6,490,104 entitled “Illumination System for Micro-Display” by Philip Landon Gleckman. As detailed at FIG. 1 of that patent, three light emitting diodes 13 mounted at a lower end of the overall device provide illumination to the micro display 11 after reflection by a polarizing beam splitter 23. The illuminated data is then reflected back from the micro display 11 on a single axis through the beam splitter 23 and an imaging lens 25 toward a viewer 31.
Other relevant teachings in the field of near-eye display devices include US Patent Publication No. 2003/0210467 by Young-Ran Song entitled “Wearable Color Display System”; and US Patent Publication No. 2004/0085649 by Piermario Repetto et al. entitled “Light Guide for display Devices of the Head-Mounted or Head-Up Type”. Other relevant teachings include US Patent Publication No. 2010/0008070 by Wai Hon Lee entitled “Back Light Module with Diffractive Couplers”.